Hydraulic feeding mechanism for a firearm



Nov. 4, 1958 J. o. EAMES 2,858,739

HYDRAULIC FEEDING MECHANISM FOR A FIREARM Filed Aug. 17, 1956 2 Sheets-Sheet 1 IEL INVENTOR. Jumes [LEumEs BY Mam M-MQM Nov. 4, 1958 Filed Aug. 17, 1956 A&

J. O. EAMES HYDRAULIC FEEDING MECHANISM FOR A FIREARM 2 Sheets-Sheet 2 W 30 L I" A INVENTOR. Jumas [I Emmes kizorneyi United States Patent James 0, Eames, Washington, Conn., assignor to the United States of America as represented bythe Secretary of the Army he Application August 17, 1956, Serial No. 604,855 4 Claims. .(CI. 89-33) This invention relates to automatic firearms and more particularly to feeding mechanisms therefor.

It is an object of this invention to provide for automatic firearms supplied with cartridges by a belt a feeding mechanism which will reduce the usual high-acceleration imparted to the belt by the intermittent demands of the firearm by extending the load developed by the feeding over a greater portion of the operating cycle.

.It is another object'of this invention is provide for automatic firearmssupplied with cartridges by a belt a feeding mechanism which maintains a bank of cartridges between the firearm and the supply container for the cartridge loaded belt to cushion the accelerative and decelerative 'forces produced by the intermittent demands of the firearm; i

It is still another object of this invention to provide for' an automatic firearm a feeding mechanism which is operated by hydraulic pressure and which is controlled by the load of cartridges within a bank provided between the firearm and the supply container for the cartridge belt.

It is a further object of this invention to provide for an automatic firearm "a feeding mechanism having hydraulically-operated double-acting 'pawls for moving the cartridge belt into a housingwhich is slidable relative to the load made upon'th'e belt by the demands of the firearm to establish a bank between the firearm and the supply container for the cartridge belt. Y

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a. description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a schematic end view of the feeding mechanism with the feed housing extension being actuated by the engagement of the pawls with the cartridge belt to the extended position to establish a bank of cartridges between the feed throat in the firearm receiver and the supply container for thecartridgebelt;

Fig. 2 is similar to Fig. l but shows the feed housing extension fully extended and the bank loaded;

. Fig.8 is similar to the other views but with the second cartridge inthe belt positioned in the feed throat and the cartridge belt being pulled towards the feed throat; and

Fig. 4 is similar to the other views and shows the bank depleted with the extension housing on the way to reload the bank. l

Shown "in the figures is afirearm having a receiver 12 and a bolt 14 mounted for reciprocation therein between a battery and a recoil position. Traversing the top of receiver 12 and fixed thereto is a rectangular boxlike feed housing 16 which receives at the feed end a cartridge belt '18 comprised of joined links 20 for releasably holding a plurality of cartridges 22 and which slidably supports such cartridge *belt during passage to a feed throat 24 opening into such receiver. Feed throat 24 is arranged tovreceive the leading one of the cartridges 22 in the cartridge belt 18 and to hold such leading cartridge ready for pick up by bolt 14 during movement-to battery position. The joined links 20 are slidably ejected from the other side of feed housing 16 after the cartridges 22 have been stripped therefrom.

Mounted for slidable movement on the feed end of feed housing 16 is a housing extension 26, the outer end of which is fixed to one end of a flexible chute 28 which is jointed to move in a plane parallel with the movement of such housing extension. The opposite end of chute 28 is fixed to the exit port of a supply container 29 which holds the bulk of the cartridge belt 18. Housing extension 26 is slidable, relative to feed housing 16, a distance equal to the distance between two cartridges in cartridge belt 18. Whereby, when housing extension 26 is moved away from feed throat 24, space is provided for two extra cartridges between such feed throat and chute 28. Consequently, two sucessive cartridges are movable toward feed throat 24 without the necessity for relative movement between cartridge belt 18 and chute 28. This results in forming a bank of cartridges which are available for feeding without movement being transferred to cartridge belt 18. Housing extension 26 is biased towards feed throat 24 by a spring 30 mounted between such housing extension and feed housing 16 and the tension of such spring is suflicient to move the cartridges 22 in the aforementioned bank to such feed throat.

Pivotally mounted to the top side of housing extension 26 is a first pawl 32 which extends downwardly for engage-' 'ment behind successive ones of the cartridges 22 in cartridge belt 18. Whereby, cartridge belt 18 is movable totension 26 is moved in a feeding direction. Such first pawl is also spring-biased so as to be slidable over the tops of the cartridges for engagement with a succeeding cartridge when housing extension 26 is moved counter to feeding direction to an extended position.

Fixedly mounted to the top of housing extension 26 is a hydraulic cylinder 34 in which there is slidably mounted a cooperating double-acting piston 36 having a rod 38 of smaller diameter'extending integrally therefrom out of such cylinder. Piston 36 forms withv cylinder 34 a chamber A which is disposed forwardly of such piston and an annular chamber B which is formed by such piston and the periphery of rod 38 and so has a lesser area than chamber A subjectable to the hydraulic pressure. Piston 36 is movable, responsive to hydraulic pressure, parallel to the movement of housing extension 26 and a distance equal to that of two cartridges in cartridge belt 18. The free end of rod 38 is fixed to a slide 40 whichmoves slidably along the underside of housing extension 26 and over cartridge belt 18.

Pivotally mounted to slide 40 is a second pawl 42 which is engageable with the cartridges 22 in the cartridge belt 18 to move such cartridge belt towards feed throat 24 when chamber A is expanded by movement of piston 36 and over such cartridges in the such chamber is contracted.

Connected to cylinder 34 on the side of chamber B is a conduit 44 which supplies hydraulic fluid directly from a source (not shown) to such chamber so that piston 36 and attached slide 40 are continually biased to the extended position. .Hydraulic fluid is supplied from the source'to chamber A by means of a conduit 46 and because of the greater area of piston 36 subjected to the pressure of the hydraulic fluid on the side of chamber A, such piston is responsive to such superior force to move rod 38 outwardly and slide 40 towards feed throat 24.

However, the passage of hydraulic fluid from conduit 46 open conduit 46 to chamber A or close such conduit and vent such chamberto atmospheric pressure on the re;

cartridge belt when turn side of the source by means of an arm 52 which extends from the shuttle member of such valve for engagement by an actuating link 54 connected to rod 38. Shuttle valve v48 is actuated by link 54 through the engagement 'of a projecting portion 58 on arm 52, with one of ,a pair of spaced lugs on link 54. One of these lugs, noted at 60, is engageable by projecting portions 58 to actuate shuttle valve 48 .to open conduit 46' to admithydraulic fluid to chamber A when piston 36 'is in the retracted position and the other one of such lugs, noted at 62, is engageable by such projection portion to close such conduit and vent such chamber When such piston is in its extended position.

Throttle valve 50 is operable to control the flow of hydraulic fluid to chamber A by the housing '64 thereof being fixedly mounted to housing extension 26 and the metering valve member 66 thereof being connected to feed housing 16. Whereby, the flow of hydraulic fluid to chamber A is controlled by the relative positions of feed housing '16 and housing extension 26. Throttle valve 50 is so arranged that the flow of fluid to chamber A is gradually reduced as housing extension 26 moves to load the bank and is fully shut olt when such housing extension is 'at the limit of its extended travel and the bank is loaded.

Operation 'Fig. lshows shuttle valve 50 positioned to vent chamber A and second pawl 42 on return to extended position by 'the pressure of the hydraulic fluid applied against the rear side of piston 36 in chamber B. The movement of second pawl 42 will continue until in position to drive the second one of the cartridges 22, noted at 2 in the figure, towards feed throat 24. When second-pawl 42 is positioned in back of cartridge 2 shuttle valve =48 is actuated by the engagement of projecting portion 58 with lug 60 toadrnit hydraulic fluid into chamber A and thereby causes piston 36 to begin its feeding stroke.

Since the leading one of the cartridges 22, notedat 1 inithe figures, is stationary in feed throat 24, and piston 36, consequently, held immovable, the hydraulic fluid 'entering chamber A causes cylinder 34 to movably react'to such pressure. As a result, housing extension 26 is actuated away fromfeed throat 24 to the extended position against the restraint of spring 30, moving first pawl 32 withit to a position to also drive on cartridge 2. When first pawl 32 is positioned behind cartridge 2, projecting portion .58 contacts lug 62 to move shuttle valve 48 so as to vent chamber A to atmospheric pressure and initiate the retracting stroke of piston 36 which moves second pawl 42 so as to drive against the cartridge, noted at 3. While second pawl 42 is being moved in back of cartridge 3, projection portion 58 is contacted by lug 60 to actuate shuttle valve 50 and admit pressure to chamber A. Piston 36 now applies force to cartridge 3 through pawl-42 but with cartridge belt 18 being held stationary by cartridge 1 in feed throat 24 this force moves housing extension 26 only a short distance to the extended position thereof where the limit of motion is reached. Here, the mechanism is stalled, as best shown by Fig. 2, by throttle valve 50 stopping the flow of hydraulic fluid to chamber A until cartridge 1 is removed from feed throat 24 by bolt 14 and chambered, at the beginning of a burst of fire.

- When cartridge 1 is picked up by bolt 14, cartridge 2 can be moved into feed throat 24. This action is initiated through pawl 32 by the bias of spring 30 since this movement is resisted now only by the inertia of housing extension 26 and attached parts and the lateral acceleration of the cartridge in chute 28 and no relative movement of cartridge. belt 18 and chute 28 is necessary. After a short movement of extension housing 26, throttle valve 50 begins to admit hydraulic fluid to chamber A and thereby the driving force moving cartridge belt- 18 is transferred from pawl 32 acting on cartridge 2, which is now the leading one of the cartridges in'cartridge belt 18,

to pawl 42 acting against cartridge 3. The feed velocity now becomes the summation of the sliding velocity of housing extension 26 and the relative velocity of cylinder 34 and piston 36.

As the movement of housing extension 26 towards feed throat 24 progresses, the gradual opening of throttle valve 50 accelerates the relative movement of cartridge belt .18 through chute" 28 until cartridge 2 is seated in fe'ed'throat 24 when piston 36 comes to rest, and the reaction of the hydraulic fluid in chamber A reverses the sliding action of housing extension'26. as best shown by Fig. 3. -As housing extension 26 begins to move toward the extended position to reload the bank of cartridges between feed throat 24 and 'chute'28, the relative motion of cartridge belt 18 and chute 28 continues, but with decreasing velocity due to the action of throttle valve 50. However,

as soon as cartridge 2 in feed throat 24 is removed therecartridge 3 is positioned in the'feed throat as besttshown by Fig. 4.

Fromthe foregoing it-is seen that at the beginningof" a burst of fire, the rapid acceleration which would have been imparted to-cartridge belt 18 by a-conventionaldirect drive feeding mechanism is considerably reduced by-the present invention through thebank formed bywthe .two

leading cartridges in such belt, which eliminates relative movement-between cartridge belt 18v and chute 28,:and through throttle valve 50 the. driving. force is. applied gradually against such cartridge belt. It is seen' further that during fire the driving force applied againsticartridge thereof and the following claims are intended to include such variations.

I claim:

1. For an automatic firearm fed with cartridges from a belt supplied through a chute from a container and having a feed throat for positioning the leading cartridge in the belt for pick up'by a bolt and a source of hydraulic fluid under pressure, a mechanism for feeding the belt to the fire arm including a housing connected to the feed end of the chute for passage of the'belt to the feedthroat therefrom and initiate the movement of the 'belti'nto'the' firearm by said pawls.

and mounted for slidable movement relative to'the firearm for establishing a bank of cartridges deliverable to the feed throat without relative movement 'between'the' belt and the chute, a pair of pawls operated by hydraulic means for moving the belt into the firearm, a shuttle valve for controlling the flow of the hydraulic fluid to said hydraulic means to actuate said pawls for engagement with successive cartridges in the belt and simultaneously urge the belt to the firearm and said housing away'from the feed throat to load the bank, a throttle valve interposed between the source of hydraulic. fluid and said shuttle valve and being responsive to the position of sa'id housing respective to the firearm for controlling the rate at which the belt is fed by saidpawls to the firearm and for stalling said pawls when said housing is moved to fully load 'the bank, and spring means for moving said housing to deliver the succeeding --cartridge in'the belt to the feed throat when the leading cartridge is'removed 2. For an automatic firearm fed with cartridges from a belt supplied through a chute from a container and having a feed throat for positioning the leading cartridge in the belt for pick up by a bolt and a source of hydraulic fluid under pressure, a mechanism for feeding the belt to the firearm including a housing connected to the feed end of the chute for passage of the belt to the feed throat and mounted for slidable movement relative to the firearm for establishing a bank of cartridges deliverable to the feed throat without relative movement between the belt and the chute, a cylinder attached to said housing and connected to the source of hydraulic fluid, a piston cooperable with said cylinder for producing relative movement therebetween responsive to the hydraulic fluid received by said cylinder, a first pawl mounted to said housing for successive engagement with the cartridges in the belt to simultaneously force the belt towards the feed throat and said housing away from said feed throat to load the bank, a second pawl connected to said piston for engagement with successive cartridges in the belt to move the belt towards the feed throat, a first hydraulic valve means responsive to position of said piston relative to said cylinder for controlling the flow of hydraulic fluid to said cylinder to actuate said first and second pawls for successive engagement with the cartridges in the belt, a second hydraulic valve means disposed between said first hydraulic valve means and said :cylinder for reducing the flow of hydraulic fluid to said cylinder as the bank approaches loaded condition and for stalling said first and second pawls when the bank is fully loaded, and a spring disposed between the firearm and said housing for biasing the belt towards said feed throat When said first and second pawls are stalled and initiating movement of said first and second pawls against the belt when the load in the bank is reduced.

3. The mechanism of claim 2 With said first hydraulic valve means including a shuttle valve for selectively admitting hydraulic fluid to said cylinder for action against said piston to force said second pawl against the belt and venting said cylinder for initiating another cycle of action against the belt when said piston reaches the limit of movement in said cylinder, and said second hydraulic valve means including a throttle valve mounted between the firearm and said housing and being responsive to the relative positions thereof for gradually reducing the flow of hydraulic fluid to said cylinder when said housing is moved to load the bank.

4. For an automatic firearm fed With cartridges from a belt supplied from a container and having a feed throat for positioning the leading cartridge in the belt for pickup by a bolt, a mechanism for feeding the belt to the firearm including a flexible chute mounted at one end to the container for slidingly supporting the belt during passage therefrom, a housing connected to the opposite end of said chute for passing the belt from said chute to the feed throat and mounted for slidable movement relative to the firearm for establishing between said chute and the feed throat a bank of cartridges deliverable to the feed throat by movement of said housing thereto without relative movement between the belt and said chute, means for biasing said housing towards the feed throat, hydraulically actuated pawls mounted to said housing for engagement with the cartridges in the belt for transferring the bias of said means to the belt, hydraulic means for actuating said pawls relative to said housing, a shuttle valve cooperating with said hydraulic means for actuating said pawls against successive cartridges in the belt to urge the belt toward the feed throat and said housing away from the feed throat to load the bank when the leading cartridge in the belt is immovably positioned in the feed throat, and a throttle valve disposed between said hydraulic means and said pawls and joined to said housing for controlling the rate at which the belt is fed to the firearm by said pawls.

References Cited in the file of this patent UNITED STATES PATENTS 2,397,501 Meyer Apr. 2, 1946 2,436,404 Slate Feb. 24, 1948 2,453,977 Eames Nov. 16, 1948 

